1 Then YHWH said to Moses, “Go in to Pharaoh, and tell him, ‘This is what YHWH, the God of the Hebrews, says: “Let my people go, that they may serve me. 2 For if you refuse to let them go, and hold them still, 3 behold, YHWH’s hand is on your livestock which are in the field, on the horses, on the donkeys, on the camels, on the herds, and on the flocks with a very grievous pestilence. 4 YHWH will make a distinction between the livestock of Israel and the livestock of Egypt; and nothing shall die of all that belongs to the children of Israel.”’” 5 YHWH appointed a set time, saying, “Tomorrow YHWH shall do this thing in the land.” Exodus 9:1-5WEB
This passage contains a positive command, with immediate application directed toward Pharaoh through Moses, "Let my people go, that they may serve me". The command is followed by a description of the penalty which God intends to visit on Pharaoh if Pharaoh does not obey.
This command is part of the Principles and Definitions. It is relevant to an understanding of the distinctive role of Prophecy as Moses is relaying a message from God, and of Stewardship as God is commanding Pharaoh to relinquish God's possession Israel.
This command was fulfilled when Aaron and Moses spoke to Pharaoh and Israel in accordance with God's commands. The command to Pharaoh was fulfilled when he eventually, begrudgingly, released Israel.